Avoided having an empty space (4)
I believe the answer is:
void
'an empty space' is the definition.
(I've seen this before)
'avoided having' is the wordplay.
'having' indicates a hidden word.
'VOID' is hidden within 'avoided'.
(Other definitions for void that I've seen before include "Nullify" , "Blank, invalid" , "Empty space or not legally binding" , "Not valid, empty space" , "Vacant; not valid" .)